i just have installed php and apache2. I made a php page and when i try to load it firefox ask me to save it!How can i resolve this?I read something about config file that i just know that i dont have!How can i generate it!?

I suspect that you have an incomplete installation. My recommendation is to un-install what you have installed and start over. For an easier approach to installing a LAMP server, I have a very brief tutorial on my web site in the Linux section.